Born and raised in the Austrian Empire, Tesla received an advanced education in engineering and physics in the 1870s and gained practical experience in the early 1880s working in telephony and at Continental Edison in the new electric power industry. He emigrated in 1884 to the United States, where he would become a naturalized citizen. He worked for a short time at the Edison Machine Works in New York City before he struck out on his own. With the help of partners to finance and market his ideas, Tesla set up laboratories and companies in New York to develop a range of electrical and mechanical devices. His alternating current (AC) induction motor and related polyphase AC patents, licensed by Westinghouse Electric in 1888, earned him a considerable amount of money and became the cornerstone of the polyphase system which that company would eventually market.

Attempting to develop inventions he could patent and market, Tesla conducted a range of experiments with mechanical oscillators/generators, electrical discharge tubes, and early X-ray imaging. He also built a wireless-controlled boat, one of the first ever exhibited. Tesla became well known as an inventor and would demonstrate his achievements to celebrities and wealthy patrons at his lab, and was noted for his showmanship at public lectures. Throughout the 1890s, Tesla pursued his ideas for wireless lighting and worldwide wireless electric power distribution in his high-voltage, high-frequency power experiments in New York and Colorado Springs. In 1893, he made pronouncements on the possibility of wireless communication with his devices. Tesla tried to put these ideas to practical use in his unfinished Wardenclyffe Tower project, an intercontinental wireless communication and power transmitter, but ran out of funding before he could complete it.[7]

After Wardenclyffe, Tesla experimented with a series of inventions in the 1910s and 1920s with varying degrees of success. Having spent most of his money, Tesla lived in a series of New York hotels, leaving behind unpaid bills. He died in New York City in January 1943.[8] Tesla's work fell into relative obscurity following his death, until 1960, when the General Conference on Weights and Measures named the SI unit of magnetic flux density the tesla in his honor.[9] There has been a resurgence in popular interest in Tesla since the 1990s.[10]

Early years

Rebuilt, Tesla's house (parish hall) in Smiljan, now in Croatia, where he was born, and the rebuilt church, where his father served. During the Yugoslav Wars, several of the buildings were severely damaged by fire. They were restored and reopened in 2006.[11]

Tesla's baptismal record, 28 June 1856

Nikola Tesla was born an ethnic Serb in the village Smiljan, Lika county, in the Austrian Empire (present day Croatia), on 10 July [O.S. 28 June] 1856.[12][13] His father, Milutin Tesla (1819–1879),[14] was an Eastern Orthodox priest.[15][16][17][18] Tesla's mother, Đuka Tesla (née Mandić; 1822–1892), whose father was also an Orthodox priest,[19] had a talent for making home craft tools and mechanical appliances and the ability to memorize Serbian epic poems. Đuka had never received a formal education. Tesla credited his eidetic memory and creative abilities to his mother's genetics and influence.[20][21] Tesla's progenitors were from western Serbia, near Montenegro.[22]

Tesla was the fourth of five children. He had three sisters, Milka, Angelina and Marica, and an older brother named Dane, who was killed in a horse riding accident when Tesla was aged five.[23] In 1861, Tesla attended primary school in Smiljan where he studied German, arithmetic, and religion.[24] In 1862, the Tesla family moved to the nearby Gospić, Lika where Tesla's father worked as parish priest. Nikola completed primary school, followed by middle school.[24] In 1870, Tesla moved far north to Karlovac[25] to attend high school at the Higher Real Gymnasium. The classes were held in German, as it was a school within the Austro-Hungarian Military Frontier.[26]

Tesla would later write that he became interested in demonstrations of electricity by his physics professor.[27] Tesla noted that these demonstrations of this "mysterious phenomena" made him want "to know more of this wonderful force".[28] Tesla was able to perform integral calculus in his head, which prompted his teachers to believe that he was cheating.[29] He finished a four-year term in three years, graduating in 1873.[30]

In 1873, Tesla returned to Smiljan. Shortly after he arrived, he contracted cholera, was bedridden for nine months and was near death multiple times. Tesla's father, in a moment of despair, (who had originally wanted him to enter the priesthood)[31] promised to send him to the best engineering school if he recovered from the illness.[25][24]

In 1874, Tesla evaded conscription into the Austro-Hungarian Army in Smiljan[32] by running away southeast of Lika to Tomingaj, near Gračac. There he explored the mountains wearing hunter's garb. Tesla said that this contact with nature made him stronger, both physically and mentally.[24] He read many books while in Tomingaj and later said that Mark Twain's works had helped him to miraculously recover from his earlier illness.[25]

In 1875, Tesla enrolled at Austrian Polytechnic in Graz, Austria, on a Military Frontier scholarship. During his first year, Tesla never missed a lecture, earned the highest grades possible, passed nine exams[25][24] (nearly twice as many as required[33]), started a Serb cultural club,[24] and even received a letter of commendation from the dean of the technical faculty to his father, which stated, "Your son is a star of first rank."[33] During his second year, Tesla came into conflict with Professor Poeschl over the Gramme dynamo, when Tesla suggested that commutators were not necessary.

Tesla claimed that he worked from 3 a.m. to 11 p.m., no Sundays or holidays excepted.[25] He was "mortified when [his] father made light of [those] hard won honors." After his father's death in 1879,[32] Tesla found a package of letters from his professors to his father, warning that unless he were removed from the school, Tesla would die through overwork. At the end of his second year, Tesla lost his scholarship and became addicted to gambling.[25][24] During his third year, Tesla gambled away his allowance and his tuition money, later gambling back his initial losses and returning the balance to his family. Tesla said that he "conquered [his] passion then and there," but later in the US he was again known to play billiards. When examination time came, Tesla was unprepared and asked for an extension to study, but was denied. He did not receive grades for the last semester of the third year and he never graduated from the university.[32]

Tesla aged 23, c. 1879

In December 1878, Tesla left Graz and severed all relations with his family to hide the fact that he dropped out of school.[32] His friends thought that he had drowned in the nearby Mur River.[34] Tesla moved to Maribor, where he worked as a draftsman for 60 florins per month. He spent his spare time playing cards with local men on the streets.[32]

In March 1879, Tesla's father went to Maribor to beg his son to return home, but he refused.[24] Nikola suffered a nervous breakdown around the same time.[34] On 24 March 1879, Tesla was returned to Gospić under police guard for not having a residence permit.

On 17 April 1879, Milutin Tesla died at the age of 60 after contracting an unspecified illness.[24] Some sources say that he died of a stroke.[35] During that year, Tesla taught a large class of students in his old school in Gospić.[24]

In January 1880, two of Tesla's uncles put together enough money to help him leave Gospić for Prague, where he was to study. He arrived too late to enroll at Charles-Ferdinand University; he had never studied Greek, a required subject; and he was illiterate in Czech, another required subject. Tesla did, however, attend lectures in philosophy at the university as an auditor but he did not receive grades for the courses.[24][36][37]

Working at Budapest Telephone Exchange

In 1881, Tesla moved to Budapest, Hungary, to work under Tivadar Puskás at a telegraph company, the Budapest Telephone Exchange. Upon arrival, Tesla realized that the company, then under construction, was not functional, so he worked as a draftsman in the Central Telegraph Office instead. Within a few months, the Budapest Telephone Exchange became functional, and Tesla was allocated the chief electrician position.[24] During his employment, Tesla made many improvements to the Central Station equipment and claimed to have perfected a telephone repeater or amplifier, which was never patented nor publicly described.[25]

Working at Edison

In 1882, Tivadar Puskás got Tesla another job in Paris with the Continental Edison Company.[38] Tesla began working in what was then a brand new industry, installing indoor incandescent lighting citywide in the form of an electric power utility. The company had several subdivisions and Tesla worked at the Société Electrique Edison, the division in the Ivry-sur-Seine suburb of Paris in charge of installing the lighting system. There he gained a great deal of practical experience in electrical engineering. Management took notice of his advanced knowledge in engineering and physics and soon had him designing and building improved versions of generating dynamos and motors.[39] They also sent him on to troubleshoot engineering problems at other Edison utilities being built around France and in Germany.

Move to the United States

Edison Machine Works on Goerck Street, New York. Tesla found the change from cosmopolitan Europe to working at this shop, located amongst the tenements on Manhattan's lower east side, a "painful surprise".[40]

In 1884, Edison manager Charles Batchelor, who had been overseeing the Paris installation, was brought back to the United States to manage the Edison Machine Works, a manufacturing division situated in New York City, and asked that Tesla be brought to the US as well.[41] In June 1884, Tesla emigrated to the United States.[42] He began working almost immediately at the Machine Works on Manhattan's Lower East Side, an overcrowded shop with a workforce of several hundred machinists, laborers, managing staff, and 20 "field engineers" struggling with the task of building the large electric utility in that city.[43] As in Paris, Tesla was working on troubleshooting installations and improving generators.[44] Historian W. Bernard Carlson notes Tesla may have met company founder Thomas Edison only a couple of times.[43] One of those times was noted in Tesla's autobiography where, after staying up all night repairing the damaged dynamos on the ocean liner SS Oregon, he ran into Batchelor and Edison, who made a quip about their "Parisian" being out all night. After Tesla told them he had been up all night fixing the Oregon Edison commented to Batchelor that "this is a damned good man".[40] One of the projects given to Tesla was to develop an arc lamp-based street lighting system.[45][46] Arc lighting was the most popular type of street lighting but it required high voltages and was incompatible with the Edison low-voltage incandescent system, causing the company to lose contracts in cities that wanted street lighting as well. Tesla's designs were never put into production, possibly because of technical improvements in incandescent street lighting or because of an installation deal that Edison cut with an arc lighting company.[47]

Tesla had been working at the Machine Works for a total of six months when he quit.[43] What event precipitated his leaving is unclear. It may have been over a bonus he did not receive, either for redesigning generators or for the arc lighting system that was shelved.[45] Tesla had previous run-ins with the Edison company over unpaid bonuses he believed he had earned.[48][49] In his own biography, Tesla stated the manager of the Edison Machine Works offered a $50,000 bonus to design "twenty-four different types of standard machines" "but it turned out to be a practical joke".[50] Later versions of this story have Thomas Edison himself offering and then reneging on the deal, quipping "Tesla, you don't understand our American humor".[51][52] The size of the bonus in either story has been noted as odd since Machine Works manager Batchelor was stingy with pay[53] and the company did not have that amount of cash (equivalent to $12 million today) on hand.[54][55] Tesla's diary contains just one comment on what happened at the end of his employment, a note he scrawled across the two pages covering 7 December 1884, to 4 January 1885, saying "Good by to the Edison Machine Works".[56][46]

Tesla Electric Light & Manufacturing

Soon after leaving the Edison company, Tesla was working on patenting an arc lighting system,[57] possibly the same one he had developed at Edison.[43] In March 1885, he met with patent attorney Lemuel W. Serrell, the same attorney used by Edison, to obtain help with submitting the patents.[57] Serrell introduced Tesla to two businessmen, Robert Lane and Benjamin Vail, who agreed to finance an arc lighting manufacturing and utility company in Tesla's name, the Tesla Electric Light & Manufacturing.[58] Tesla worked for the rest of the year obtaining the patents that included an improved DC generator, the first patents issued to Tesla in the US, and building and installing the system in Rahway, New Jersey[59] Tesla's new system gained notice in the technical press, which commented on its advanced features.

The investors showed little interest in Tesla's ideas for new types of alternating current motors and electrical transmission equipment. After the utility was up and running in 1886, they decided that the manufacturing side of the business was too competitive and opted to simply run an electric utility.[60] They formed a new utility company, abandoning Tesla's company and leaving the inventor penniless.[60] Tesla even lost control of the patents he had generated, since he had assigned them to the company in exchange for stock.[60] He had to work at various electrical repair jobs and as a ditch digger for $2 per day. Later in life Tesla would recount that part of 1886 as a time of hardship, writing "My high education in various branches of science, mechanics and literature seemed to me like a mockery".[61][60]

AC and the induction motor

Drawing from U.S. Patent 381,968, illustrating principle of Tesla's alternating current induction motor

In late 1886, Tesla met Alfred S. Brown, a Western Union superintendent, and New York attorney Charles F. Peck. The two men were experienced in setting up companies and promoting inventions and patents for financial gain.[62] Based on Tesla's new ideas for electrical equipment, including a thermo-magnetic motor idea,[63] they agreed to back the inventor financially and handle his patents. Together they formed the Tesla Electric Company in April 1887, with an agreement that profits from generated patents would go 1/3 to Tesla, 1/3 to Peck and Brown, and 1/3 to fund development.[62] They set up a laboratory for Tesla at 89 Liberty Street in Manhattan, where he worked on improving and developing new types of electric motors, generators, and other devices.

In 1887, Tesla developed an induction motor that ran on alternating current (AC), a power system format that was rapidly expanding in Europe and the United States because of its advantages in long-distance, high-voltage transmission. The motor used polyphase current, which generated a rotating magnetic field to turn the motor (a principle that Tesla claimed to have conceived in 1882).[64][65][66] This innovative electric motor, patented in May 1888, was a simple self-starting design that did not need a commutator, thus avoiding sparking and the high maintenance of constantly servicing and replacing mechanical brushes.[67][68]

Along with getting the motor patented, Peck and Brown arranged to get the motor publicized, starting with independent testing to verify it was a functional improvement, followed by press releases sent to technical publications for articles to run concurrent with the issue of the patent.[69] Physicist William Arnold Anthony (who tested the motor) and Electrical World magazine editor Thomas Commerford Martin arranged for Tesla to demonstrate his AC motor on 16 May 1888 at the American Institute of Electrical Engineers.[69][70] Engineers working for the Westinghouse Electric & Manufacturing Company reported to George Westinghouse that Tesla had a viable AC motor and related power system—something Westinghouse needed for the alternating current system he was already marketing. Westinghouse looked into getting a patent on a similar commutator-less, rotating magnetic field-based induction motor developed in 1885 and presented in a paper in March 1888 by Italian physicist Galileo Ferraris, but decided that Tesla's patent would probably control the market.[71][72]

In July 1888, Brown and Peck negotiated a licensing deal with George Westinghouse for Tesla's polyphase induction motor and transformer designs for $60,000 in cash and stock and a royalty of $2.50 per AC horsepower produced by each motor. Westinghouse also hired Tesla for one year for the large fee of $2,000 ($55,800 in today's dollars[73]) per month to be a consultant at the Westinghouse Electric & Manufacturing Company's Pittsburgh labs.[74]

During that year, Tesla worked in Pittsburgh, helping to create an alternating current system to power the city's streetcars. He found it a frustrating period because of conflicts with the other Westinghouse engineers over how best to implement AC power. Between them, they settled on a 60-cycle AC system that Tesla proposed (to match the working frequency of Tesla's motor), but they soon found that it would not work for streetcars, since Tesla's induction motor could run only at a constant speed. They ended up using a DC traction motor instead.[75][76]

Market turmoil

Tesla's demonstration of his induction motor and Westinghouse's subsequent licensing of the patent, both in 1888, came at the time of extreme competition between electric companies.[77][78] The three big firms, Westinghouse, Edison, and Thomson-Houston, were trying to grow in a capital-intensive business while financially undercutting each other. There was even a "War of Currents" propaganda campaign going on with Edison Electric trying to claim their direct current system was better and safer than the Westinghouse alternating current system.[79][80] Competing in this market meant Westinghouse would not have the cash or engineering resources to develop Tesla's motor and the related polyphase system right away.[81]

Two years after signing the Tesla contract, Westinghouse Electric was in trouble. The near collapse of Barings Bank in London triggered the financial panic of 1890, causing investors to call in their loans to W.E (Westinghouse Electric).[82] The sudden cash shortage forced the company to refinance its debts. The new lenders demanded that Westinghouse cut back on what looked like excessive spending on acquisition of other companies, research, and patents, including the per motor royalty in the Tesla contract.[83][84] At that point, the Tesla induction motor had been unsuccessful and was stuck in development.[82][81] Westinghouse was paying a $15,000-a-year guaranteed royalty[85] even though operating examples of the motor were rare and polyphase power systems needed to run it were even rarer.[82][67] In early 1891, George Westinghouse explained his financial difficulties to Tesla in stark terms, saying that, if he did not meet the demands of his lenders, he would no longer be in control of Westinghouse Electric and Tesla would have to "deal with the bankers" to try to collect future royalties.[86] The advantages of having Westinghouse continue to champion the motor probably seemed obvious to Tesla and he agreed to release the company from the royalty payment clause in the contract.[86][87] Six years later Westinghouse would purchase Tesla's patent for a lump sum payment of $216,000 as part of a patent-sharing agreement signed with General Electric (a company created from the 1892 merger of Edison and Thomson-Houston).[88][89][90]

New York laboratories

The money Tesla made from licensing his AC patents made him independently wealthy and gave him the time and funds to pursue his own interests.[91] In 1889, Tesla moved out of the Liberty Street shop Peck and Brown had rented and for the next dozen years would work out of a series of workshop/laboratory spaces in Manhattan. These included a lab at 175 Grand Street (1889–1892), the fourth floor of 33–35 South Fifth Avenue (1892–1895), and sixth and seventh floors of 46 & 48 East Houston Street (1895–1902).[92][93] Tesla and his hired staff would conduct some of his most significant work in these workshops.

Tesla coil

In the summer of 1889, Tesla traveled to the 1889 Exposition Universelle in Paris and learned of Heinrich Hertz' 1886–88 experiments that proved the existence of electromagnetic radiation, including radio waves.[94] Tesla found this new discovery "refreshing" and decided to explore it more fully. In repeating, and then expanding on, these experiments, Tesla tried powering a Ruhmkorff coil with a high speed alternator he had been developing as part of an improved arc lighting system but found that the high-frequency current overheated the iron core and melted the insulation between the primary and secondary windings in the coil. To fix this problem Tesla came up with his Tesla coil with an air gap instead of insulating material between the primary and secondary windings and an iron core that could be moved to different positions in or out of the coil.[95]

Wireless lighting

After 1890, Tesla experimented with transmitting power by inductive and capacitive coupling using high AC voltages generated with his Tesla coil.[99] He attempted to develop a wireless lighting system based on near-field inductive and capacitive coupling and conducted a series of public demonstrations where he lit Geissler tubes and even incandescent light bulbs from across a stage.[100] He would spend most of the decade working on variations of this new form of lighting with the help of various investors but none of the ventures succeeded in making a commercial product out of his findings.[101]

Steam-powered oscillating generator

Trying to come up with a better way to generate alternating current, Tesla developed a steam powered reciprocating electricity generator. He patented it in 1893 and introduced it at the Chicago World's Columbian Exposition that year. Steam would be forced into the oscillator and rush out through a series of ports, pushing a piston up and down that was attached to an armature. The magnetic armature vibrated up and down at high speed, producing an alternating magnetic field. This induced alternating electric current in the wire coils located adjacent. It did away with the complicated parts of a steam engine/generator, but never caught on as a feasible engineering solution to generate electricity.[105][106]

Polyphase System and the Columbian Exposition

A Westinghouse display of the "Tesla Polyphase System" at Chicago's 1893 Columbian Exposition

At the beginning of 1893, Westinghouse engineer Benjamin Lamme had made great progress developing an efficient version of Tesla's induction motor, and Westinghouse Electric started branding their complete polyphase AC system as the "Tesla Polyphase System". They believed that Tesla's patents gave them patent priority over other AC systems.[107]

Westinghouse Electric asked Tesla to participate in the 1893 World's Columbian Exposition in Chicago where the company had a large space in a building devoted to electrical exhibits. Westinghouse Electric won the bid to light the Exposition with alternating current and it was a key event in the history of AC power, as the company demonstrated to the American public the safety, reliability, and efficiency of a fully integrated alternating current system.[108][109][110] Tesla showed a series of electrical effects related to alternating current as well as his wireless lighting system, using a demonstration he had previously performed throughout America and Europe;[111] these included using high-voltage, high-frequency alternating current to light a wireless gas-discharge lamp.[112]

An observer noted:

Within the room were suspended two hard-rubber plates covered with tin foil. These were about fifteen feet apart, and served as terminals of the wires leading from the transformers. When the current was turned on, the lamps or tubes, which had no wires connected to them, but lay on a table between the suspended plates, or which might be held in the hand in almost any part of the room, were made luminous. These were the same experiments and the same apparatus shown by Tesla in London about two years previous, "where they produced so much wonder and astonishment".[113]

Tesla also explained the principles of the rotating magnetic field in an induction motor by demonstrating how to make a copper egg stand on end, using a device that he constructed known as the Egg of Columbus[114] and introduced his new steam powered oscillator AC generator.

Consulting on Niagara

In 1893, Edward Dean Adams, who headed up the Niagara FallsCataract Construction Company, sought Tesla's opinion on what system would be best to transmit power generated at the falls. Over several years, there had been a series of proposals and open competitions on how best to use power generated by the falls. Among the systems proposed by several US and European companies were two-phase and three-phase AC, high-voltage DC, and compressed air. Adams pumped Tesla for information about the current state of all the competing systems. Tesla advised Adams that a two-phased system would be the most reliable, and that there was a Westinghouse system to light incandescent bulbs using two-phase alternating current. The company awarded a contract to Westinghouse Electric for building a two-phase AC generating system at the Niagara Falls, based on Tesla's advice and Westinghouse's demonstration at the Columbian Exposition that they could build a complete AC system. At the same time, a further contract was awarded to General Electric to build the AC distribution system.[115]

The Nikola Tesla Company

In 1895, Edward Dean Adams, impressed with what he saw when he toured Tesla's lab, agreed to help found the Nikola Tesla Company, set up to fund, develop, and market a variety of previous Tesla patents and inventions as well as new ones. Alfred Brown signed on, bringing along patents developed under Peck and Brown. The board was filled out with William Birch Rankine and Charles F. Coaney.[116] It found few investors; the mid-1890s was a tough time financially, and the wireless lighting and oscillators patents it was set up to market never panned out. The company would handle Tesla's patents for decades to come.

Lab fire

In the early morning hours of 13 March 1895, the South Fifth Avenue building that housed Tesla's lab caught fire. It started in the basement of the building and was so intense Tesla's 4th floor lab burned and collapsed into the second floor. The fire not only set back Tesla's ongoing projects, it destroyed a collection of early notes and research material, models, and demonstration pieces, including many that had been exhibited at the 1893 Worlds Colombian Exposition. Tesla told The New York Times "I am in too much grief to talk. What can I say?"[24] After the fire Tesla moved to 46 & 48 East Houston Street and rebuilt his lab on the 6th and 7th floors.

X-ray experimentation

Starting in 1894, Tesla began investigating what he referred to as radiant energy of "invisible" kinds after he had noticed damaged film in his laboratory in previous experiments[117] (later identified as "Roentgen rays" or "X-Rays"). His early experiments were with Crookes tubes, a cold cathode electrical discharge tube. Tesla may have inadvertently captured an X-ray image—predating, by a few weeks, Wilhelm Röntgen's December 1895 announcement of the discovery of X-rays when he tried to photograph Mark Twain illuminated by a Geissler tube, an earlier type of gas discharge tube. The only thing captured in the image was the metal locking screw on the camera lens.[118]

In March 1896, after hearing of Wilhelm Röntgen's discovery of X-ray and X-ray imaging (radiography),[120] Tesla proceeded to do his own experiments in X-ray imaging, developing a high energy single terminal vacuum tube of his own design that had no target electrode and that worked from the output of the Tesla Coil (the modern term for the phenomenon produced by this device is bremsstrahlung or braking radiation). In his research, Tesla devised several experimental setups to produce X-rays. Tesla held that, with his circuits, the "instrument will ... enable one to generate Roentgen rays of much greater power than obtainable with ordinary apparatus".[121]

Tesla noted the hazards of working with his circuit and single-node X-ray-producing devices. In his many notes on the early investigation of this phenomenon, he attributed the skin damage to various causes. He believed early on that damage to the skin was not caused by the Roentgen rays, but by the ozone generated in contact with the skin, and to a lesser extent, by nitrous acid. Tesla incorrectly believed that X-rays were longitudinal waves, such as those produced in waves in plasmas. These plasma waves can occur in force-free magnetic fields.[122][123]

On 11 July 1934, the New York Herald Tribune published an article on Tesla, in which he recalled an event that would occasionally take place while experimenting with his single-electrode vacuum tubes; a minute particle would break off the cathode, pass out of the tube, and physically strike him:

Tesla said he could feel a sharp stinging pain where it entered his body, and again at the place where it passed out. In comparing these particles with the bits of metal projected by his "electric gun," Tesla said, "The particles in the beam of force ... will travel much faster than such particles ... and they will travel in concentrations".[124]

Radio remote control

In 1898, Tesla demonstrated a boat that used a coherer-based radio control—which he dubbed "telautomaton"—to the public during an electrical exhibition at Madison Square Garden.[125] The crowd that witnessed the demonstration made outrageous claims about the workings of the boat, such as magic, telepathy, and being piloted by a trained monkey hidden inside.[126] Tesla tried to sell his idea to the US military as a type of radio-controlled torpedo, but they showed little interest.[127] Remote radio control remained a novelty until World War I and afterward, when a number of countries used it in military programs.[128] Tesla took the opportunity to further demonstrate "Teleautomatics" in an address to a meeting of the Commercial Club in Chicago, while he was travelling to Colorado Springs, on 13 May 1899.[24]

Wireless power

From the 1890s through 1906, Tesla spent a great deal of his time and fortune on a series of projects trying to develop the transmission of electrical power without wires. It was an expansion of his idea of using coils to transmit power that he had been demonstrating in wireless lighting. He saw this as not only a way to transmit large amounts of power around the world but also, as he had pointed out in his earlier lectures, a way to transmit worldwide communications.

At the time Tesla was formulating his ideas, there was no feasible way to wirelessly transmit communication signals over long distances, let alone large amounts of power. Tesla had studied radio waves early on, and came to the conclusion that part of existing study on them, by Hertz, was incorrect.[129][130][131] Also, this new form of radiation was widely considered at the time to be a short-distance phenomenon that seemed to die out in less than a mile.[132] Tesla noted that, even if theories on radio waves were true, they were totally worthless for his intended purposes since this form of "invisible light" would diminish over distance just like any other radiation and would travel in straight lines right out into space, becoming "hopelessly lost".[133]

By the mid-1890s, Tesla was working on the idea that he might be able to conduct electricity long distance through the Earth or the atmosphere, and began working on experiments to test this idea including setting up a large resonance transformer magnifying transmitter in his East Houston Street lab.[134][135][136] Seeming to borrow from a common idea at the time that the Earth's atmosphere was conductive,[137][138] he proposed a system composed of balloons suspending, transmitting, and receiving, electrodes in the air above 30,000 feet (9,100 m) in altitude, where he thought the lower pressure would allow him to send high voltages (millions of volts) long distances.

Colorado Springs

To further study the conductive nature of low pressure air, Tesla set up an experimental station at high altitude in Colorado Springs during 1899.[139][140][141][142] There he could safely operate much larger coils than in the cramped confines of his New York lab, and an associate had made an arrangement for the El Paso Power Company to supply alternating current free of charge.[142] To fund his experiments, he convinced John Jacob Astor IV to invest $100,000 ($3,011,600 in today's dollars[73]) to become a majority share holder in the Nikola Tesla Company. Astor thought he was primarily investing in the new wireless lighting system. Instead, Tesla used the money to fund his Colorado Springs experiments.[24][143] Upon his arrival, he told reporters that he planned to conduct wireless telegraphy experiments, transmitting signals from Pikes Peak to Paris.[144]

There, he conducted experiments with a large coil operating in the megavolts range, producing artificial lightning (and thunder) consisting of millions of volts and discharges of up to 135 feet (41 m) in length,[146] and, at one point, inadvertently burned out the generator in El Paso, causing a power outage.[147] The observations he made of the electronic noise of lightning strikes, led him to (incorrectly) conclude[148][149] that he could use the entire globe of the Earth to conduct electrical energy.

During his time at his laboratory, Tesla observed unusual signals from his receiver which he speculated to be communications from another planet. He mentioned them in a letter to a reporter in December 1899[150] and to the Red Cross Society in December 1900.[151][152] Reporters treated it as a sensational story and jumped to the conclusion Tesla was hearing signals from Mars.[151] He expanded on the signals he heard in a 9 February 1901 Collier's Weekly article entitled "Talking With Planets", where he said it had not been immediately apparent to him that he was hearing "intelligently controlled signals" and that the signals could come have from Mars, Venus, or other planets.[152] It has been hypothesized that he may have intercepted Guglielmo Marconi's European experiments in July 1899—Marconi may have transmitted the letter S (dot/dot/dot) in a naval demonstration, the same three impulses that Tesla hinted at hearing in Colorado[152]—or signals from another experimenter in wireless transmission.[153]

Tesla had an agreement with the editor of The Century Magazine to produce an article on his findings. The magazine sent a photographer to Colorado to photograph the work being done there. The article, titled "The Problem of Increasing Human Energy", appeared in the June 1900 edition of the magazine. He explained the superiority of the wireless system he envisioned but the article was more of a lengthy philosophical treatise than an understandable scientific description of his work,[154] illustrated with what were to become iconic images of Tesla and his Colorado Springs experiments.

Wardenclyffe

Tesla made the rounds in New York trying to find investors for what he thought would be a viable system of wireless transmission, wining and dining them at the Waldorf-Astoria's Palm Garden (the hotel where he was living at the time), The Players Club, and Delmonico's.[155] In March 1901, he obtained $150,000 ($4,517,400 in today's dollars[73]) from J. Pierpont Morgan in return for a 51% share of any generated wireless patents, and began planning the Wardenclyffe Tower facility to be built in Shoreham, New York, 100 miles (161 km) east of the city on the North Shore of Long Island.[156]

By July 1901, Tesla had expanded his plans to build a more powerful transmitter to leap ahead of Marconi's radio-based system, which Tesla thought was a copy of his own.[151] He approached Morgan to ask for more money to build the larger system, but Morgan refused to supply any further funds.[157] In December 1901, Marconi successfully transmitted the letter S from England to Newfoundland, defeating Tesla in the race to be first to complete such a transmission. A month after Marconi's success, Tesla tried to get Morgan to back an even larger plan to transmit messages and power by controlling "vibrations throughout the globe".[151] Over the next five years, Tesla wrote more than 50 letters to Morgan, pleading for and demanding additional funding to complete the construction of Wardenclyffe. Tesla continued the project for another nine months into 1902. The tower was erected to its full height of 187 feet (57 m).[153] In June 1902, Tesla moved his lab operations from Houston Street to Wardenclyffe.[156]

Investors on Wall Street were putting their money into Marconi's system, and some in the press began turning against Tesla's project, claiming it was a hoax.[158] The project came to a halt in 1905, and in 1906, the financial problems and other events may have led to what Tesla biographer Marc J. Seifer suspects was a nervous breakdown on Tesla's part.[159] Tesla mortgaged the Wardenclyffe property to cover his debts at the Waldorf-Astoria, which eventually mounted to $20,000 ($500,300 in today's dollars[73]).[160] He lost the property in foreclosure in 1915, and in 1917 the Tower was demolished by the new owner to make the land a more viable real estate asset.

Later years

After Wardenclyffe closed, Tesla continued to write to Morgan; after "the great man" died, Tesla wrote to Morgan's son Jack, trying to get further funding for the project. In 1906, Tesla opened offices at 165 Broadway in Manhattan, trying to raise further funds by developing and marketing his patents. He went on to have offices at the Metropolitan Life Tower from 1910 to 1914; rented for a few months at the Woolworth Building, moving out because he could not afford the rent; and then to office space at 8 West 40th Street from 1915 to 1925. After moving to 8 West 40th Street, he was effectively bankrupt. Most of his patents had run out and he was having trouble with the new inventions he was trying to develop.[161]

Bladeless turbine

On his 50th birthday, in 1906, Tesla demonstrated a 200 horsepower (150 kilowatts) 16,000 rpm bladeless turbine. During 1910–1911, at the Waterside Power Station in New York, several of his bladeless turbine engines were tested at 100–5,000 hp.[162] Tesla worked with several companies including from 1919–1922 in Milwaukee, for Allis-Chalmers.[163][164] He spent most of his time trying to perfect the Tesla turbine with Hans Dahlstrand, the head engineer at the company, but engineering difficulties meant it was never made into a practical device.[165] Tesla did license the idea to a precision instrument company and it found use in the form of luxury car speedometers and other instruments.[166]

Wireless lawsuits

When World War I broke out, the British cut the transatlantic telegraph cable linking the US to Germany in order to control the flow of information between the two countries. They also tried to shut off German wireless communication to and from the US by having the US Marconi Company sue the German radio company Telefunken for patent infringement.[167] Telefunken brought in the physicists Jonathan Zenneck and Karl Ferdinand Braun for their defense, and hired Tesla as a witness for two years for $1,000 a month. The case stalled and then went moot when the US entered the war against Germany in 1917.[167][168]

In 1915, Tesla attempted to sue the Marconi Company for infringement of his wireless tuning patents. Marconi's initial radio patent had been awarded in the US in 1897, but his 1900 patent submission covering improvements to radio transmission had been rejected several times, before it was finally approved in 1904, on the grounds that it infringed on other existing patents including two 1897 Tesla wireless power tuning patents.[169][130][170] Tesla's 1915 case went nowhere,[171] but in a related case, where the Marconi Company tried to sue the US government over WWI patent infringements, a Supreme Court of the United States 1943 decision restored the prior patents of Oliver Lodge, John Stone, and Tesla.[172] The court declared that their decision had no bearing on Marconi's claim as the first to achieve radio transmission, just that since Marconi's claim to certain patented improvements were questionable, the company could not claim infringement on those same patents.[173][130]

Nobel Prize rumors

On 6 November 1915, a Reuters news agency report from London had the 1915 Nobel Prize in Physics awarded to Thomas Edison and Nikola Tesla; however, on 15 November, a Reuters story from Stockholm stated the prize that year was being awarded to Sir William Henry Bragg and William Lawrence Bragg "for their services in the analysis of crystal structure by means of X-rays".[174][175][176] There were unsubstantiated rumors at the time that either Tesla or Edison had refused the prize.[174] The Nobel Foundation said, "Any rumor that a person has not been given a Nobel Prize because he has made known his intention to refuse the reward is ridiculous"; a recipient could decline a Nobel Prize only after he is announced a winner.[174]

There have been subsequent claims by Tesla biographers that Edison and Tesla were the original recipients and that neither was given the award because of their animosity toward each other; that each sought to minimize the other's achievements and right to win the award; that both refused ever to accept the award if the other received it first; that both rejected any possibility of sharing it; and even that a wealthy Edison refused it to keep Tesla from getting the $20,000 prize money.[174][21]

In the years after these rumors, neither Tesla nor Edison won the prize (although Edison did receive one of 38 possible bids in 1915 and Tesla did receive one of 38 possible bids in 1937).[177]

Order of the White Eagle, I Class, Government of Yugoslavia (1936)[181]

Order of the White Lion, I Class, Government of Czechoslovakia (1937)[181]

University of Paris Medal (1937)

The Medal of the University St. Clement of Ochrida, Sofia, Bulgaria (1939)

Tesla attempted to market several devices based on the production of ozone. These included his 1900 Tesla Ozone Company selling an 1896 patented device based on his Tesla Coil, used to bubble ozone through different types of oils to make a therapeutic gel.[182] He also tried to develop a variation of this a few years later as a room sanitizer for hospitals.[183]

Tesla theorized that the application of electricity to the brain enhanced intelligence. In 1912, he crafted "a plan to make dull students bright by saturating them unconsciously with electricity," wiring the walls of a schoolroom and, "saturating [the schoolroom] with infinitesimal electric waves vibrating at high frequency. The whole room will thus, Mr. Tesla claims, be converted into a health-giving and stimulating electromagnetic field or 'bath.'"[184] The plan was, at least provisionally, approved by then superintendent of New York City schools, William H. Maxwell.[184]

Before World War I, Tesla sought overseas investors. After the war started, Tesla lost the funding he was receiving from his patents in European countries.

In the August 1917 edition of the magazine Electrical Experimenter, Tesla postulated that electricity could be used to locate submarines via using the reflection of an "electric ray" of "tremendous frequency," with the signal being viewed on a fluorescent screen (a system that has been noted to have a superficial resemblance to modern radar).[185] Tesla was incorrect in his assumption that high frequency radio waves would penetrate water.[186]Émile Girardeau, who helped develop France's first radar system in the 1930s, noted in 1953 that Tesla's general speculation that a very strong high-frequency signal would be needed was correct. Girardeau said, "(Tesla) was prophesying or dreaming, since he had at his disposal no means of carrying them out, but one must add that if he was dreaming, at least he was dreaming correctly".[187]

In 1928, Tesla received U.S. Patent 1,655,114, for a biplane capable of taking off vertically (VTOL aircraft) and then of being "gradually tilted through manipulation of the elevator devices" in flight until it was flying like a conventional plane.[188] Tesla thought the plane would sell for less than $1,000,[189] although the aircraft has been described as impractical.[190] This would be his last patent and at this time Tesla closed his last office at 350 Madison Ave., which he had moved into two years earlier.

Living circumstances

Since 1900, Tesla had been living at the Waldorf Astoria in New York running up a large bill.[191] In 1922, he moved to St. Regis Hotel and would follow a pattern from then on of moving to a new hotel every few years leaving behind unpaid bills.[192][193]

Tesla would walk to the park every day to feed the pigeons. He took to feeding them at the window of his hotel room and bringing the injured ones in to nurse back to health.[193][194][195] He said that he had been visited by a specific injured white pigeon daily. Tesla spent over $2,000, including building a device that comfortably supported her so her bones could heal, to fix her broken wing and leg.[32] Tesla stated:

I have been feeding pigeons, thousands of them for years. But there was one, a beautiful bird, pure white with light grey tips on its wings; that one was different. It was a female. I had only to wish and call her and she would come flying to me. I loved that pigeon as a man loves a woman, and she loved me. As long as I had her, there was a purpose to my life.[196]

In 1934, Tesla moved to the Hotel New Yorker, and Westinghouse Electric & Manufacturing Company began paying him $125 per month as well as paying his rent, expenses the Company would pay for the rest of Tesla's life. Accounts of how this came about vary. Several sources say Westinghouse was worried (or warned) about potential bad publicity surrounding the impoverished conditions under which their former star inventor was living.[198][199][200][201] The payment has been described as being couched as a "consulting fee" to get around Tesla's aversion to accept charity, or by one biographer (Marc Seifer) as a type of unspecified settlement.[200]

Birthday press conferences

In 1931, a young science fiction writer whom Tesla befriended, Kenneth Swezey, organized a celebration for the inventor's 75th birthday.[202] Tesla received congratulatory letters from more than 70 pioneers in science and engineering, including Albert Einstein,[203] and he was also featured on the cover of Time magazine.[204] The cover caption "All the world's his power house" noted his contribution to electrical power generation.

The party went so well that Tesla made it an annual event, an occasion where he would put out a large spread of food and drink featuring dishes of his own creation, to invite the press to see his inventions and hear stories about past exploits and views on current events, including sometimes odd or baffling claims.[205][206]

At the 1932 party, Tesla claimed he had invented a motor that would run on cosmic rays.[206]

In 1933 at age 77, Tesla told reporters at the event that, after thirty-five years of work, he was on the verge of producing proof of a new form of energy. He claimed it was a theory of energy that was "violently opposed" to Einsteinian physics, and could be tapped with an apparatus that would be cheap to run and last 500 years. He also told reporters he was working on a way to transmit individualized private radio wavelengths, working on breakthroughs in metallurgy, and developing a way to photograph the retina to record thought.[207]

At the 1934 occasion, Tesla told reporters he had designed a superweapon he claimed would end all war.[208][209] He would call it "teleforce", but was usually referred to as his death ray.[210] Tesla described it as a defensive weapon that would be put up along the border of a country to be used against attacking ground-based infantry or aircraft. Tesla never revealed detailed plans of how the weapon worked during his lifetime, but in 1984, they surfaced at the Nikola Tesla Museum archive in Belgrade.[211] The treatise, The New Art of Projecting Concentrated Non-dispersive Energy through the Natural Media, described an open-ended vacuum tube with a gas jet seal that allows particles to exit, a method of charging slugs of tungsten or mercury to millions of volts, and directing them in streams (through electrostatic repulsion).[212][206] Tesla tried to interest the US War Department,[213] the United Kingdom, the Soviet Union, and Yugoslavia in the device.[214]

In 1935 at his 79th birthday party, Tesla covered many topics. He claimed to have discovered the cosmic ray in 1896 and invented a way to produce direct current by induction, and made many claims about his mechanical oscillator.[215] Describing the device (which he expected would earn him $100 million within two years) he told reporters that a version of his oscillator had caused an earthquake in his 46 East Houston Street lab and neighboring streets in downtown New York City in 1898.[215] He went on to tell reporters his oscillator could destroy the Empire State Building with 5 lbs of air pressure.[216] He also explained a new technique he developed using his oscillators he called "Telegeodynamics", using it to transmit vibrations into the ground that he claimed would work over any distance to be used for communication or locating underground mineral deposits.[124]

In his 1937 Grand Ballroom of Hotel New Yorker event, Tesla received the "Order of the White Lion" from the Czechoslovakia ambassador and a medal from the Yugoslavian ambassador.[206] On questions concerning the death ray, Tesla stated, "But it is not an experiment ... I have built, demonstrated and used it. Only a little time will pass before I can give it to the world."

Death

In the fall of 1937 at the age of 81, after midnight one night, Tesla left the Hotel New Yorker to make his regular commute to the cathedral and the library to feed the pigeons. While crossing a street a couple of blocks from the hotel, Tesla was unable to dodge a moving taxicab and was thrown to the ground. His back was severely wrenched and three of his ribs were broken in the accident. The full extent of his injuries were never known; Tesla refused to consult a doctor, an almost lifelong custom, and never fully recovered.[33][217]

On 7 January 1943, at the age of 86, Tesla died alone in Room 3327 of the New Yorker Hotel. His body was later found by maid Alice Monaghan after she had entered Tesla's room, ignoring the "do not disturb" sign that Tesla had placed on his door two days earlier. Assistant medical examiner H.W. Wembley examined the body and ruled that the cause of death had been coronary thrombosis.[24]

[Tesla's] thoughts and efforts during at least the past 15 years were primarily of a speculative, philosophical, and somewhat promotional character often concerned with the production and wireless transmission of power; but did not include new, sound, workable principles or methods for realizing such results.[218]

Estate

In 1952, following pressure from Tesla's nephew, Sava Kosanović, Tesla's entire estate was shipped to Belgrade in 80 trunks marked N.T.[24] In 1957, Kosanović's secretary Charlotte Muzar transported Tesla's ashes from the United States to Belgrade.[24] The ashes are displayed in a gold-plated sphere on a marble pedestal in the Nikola Tesla Museum.[220]

Patents

Tesla obtained around 300 patents worldwide for his inventions.[221] Some of Tesla's patents are not accounted for, and various sources have discovered some that have lain hidden in patent archives. There are a minimum of 278 known patents[221] issued to Tesla in 26 countries. Many of Tesla's patents were in the United States, Britain, and Canada, but many other patents were approved in countries around the globe.[222] Many inventions developed by Tesla were not put into patent protection.

Personal life

Tesla worked every day from 9:00a.m. until 6:00p.m. or later, with dinner from exactly 8:10 p.m., at Delmonico's restaurant and later the Waldorf-Astoria Hotel. Tesla would telephone his dinner order to the headwaiter, who also could be the only one to serve him. "The meal was required to be ready at eight o'clock ... He dined alone, except on the rare occasions when he would give a dinner to a group to meet his social obligations. Tesla would then resume his work, often until 3:00a.m."[223]

For exercise, Tesla walked between 8 and 10 miles (13 and 16 km) per day. He curled his toes one hundred times for each foot every night, saying that it stimulated his brain cells.[224]

In an interview with newspaper editor Arthur Brisbane, Tesla said that he did not believe in telepathy, stating, "Suppose I made up my mind to murder you," he said, "In a second you would know it. Now, isn't that wonderful? By what process does the mind get at all this?" In the same interview, Tesla said that he believed that all fundamental laws could be reduced to one.[225]

Tesla became a vegetarian in his later years, living on only milk, bread, honey, and vegetable juices.[209][226]

Appearance

Tesla was 6 feet 2 inches (1.88 m) tall and weighed 142 pounds (64 kg), with almost no weight variance from 1888 to about 1926. His appearance was described by newspaper editor Arthur Brisbane as "almost the tallest, almost the thinnest and certainly the most serious man who goes to Delmonico's regularly".[225][227] He was an elegant, stylish figure in New York City, meticulous in his grooming, clothing, and regimented in his daily activities, an appearance he maintained as to further his business relationships.[228] He was also described as having light eyes, "very big hands", and "remarkably big" thumbs.[225]

Eidetic memory

Tesla read many works, memorizing complete books, and supposedly possessed a photographic memory.[229] He was a polyglot, speaking eight languages: Serbo-Croatian, Czech, English, French, German, Hungarian, Italian, and Latin.[230] Tesla related in his autobiography that he experienced detailed moments of inspiration. During his early life, Tesla was repeatedly stricken with illness. He suffered a peculiar affliction in which blinding flashes of light would appear before his eyes, often accompanied by visions.[229] Often, the visions were linked to a word or idea he might have come across; at other times they would provide the solution to a particular problem he had encountered. Just by hearing the name of an item, he would be able to envision it in realistic detail.[229] Tesla would visualize an invention in his mind with extreme precision, including all dimensions, before moving to the construction stage, a technique sometimes known as picture thinking. He typically did not make drawings by hand but worked from memory. Beginning in his childhood, Tesla had frequent flashbacks to events that had happened previously in his life.[229]

Sleep habits

Tesla claimed never to sleep more than two hours per night.[231] However, he did admit to "dozing" from time to time "to recharge his batteries".[224] During his second year of study at Graz, Tesla developed a passionate proficiency for billiards, chess, and card-playing, sometimes spending more than 48 hours in a stretch at a gaming table.[232] On one occasion at his laboratory, Tesla worked for a period of 84 hours without rest.[233] Kenneth Swezey, a journalist whom Tesla had befriended, confirmed that Tesla rarely slept. Swezey recalled one morning when Tesla called him at 3 a.m.: "I was sleeping in my room like one dead ... Suddenly, the telephone ring awakened me ... [Tesla] spoke animatedly, with pauses, [as he] ... work[ed] out a problem, comparing one theory to another, commenting; and when he felt he had arrived at the solution, he suddenly closed the telephone."[224]

Relationships

Tesla never married, explaining that his chastity was very helpful to his scientific abilities.[229] He once said in earlier years that he felt he could never be worthy enough for a woman, considering women superior in every way. His opinion had started to sway in later years when he felt that women were trying to outdo men and make themselves more dominant. This "new woman" was met with much indignation from Tesla, who felt that women were losing their femininity by trying to be in power. In an interview with the Galveston Daily News on 10 August 1924 he stated, "In place of the soft voiced, gentle woman of my reverent worship, has come the woman who thinks that her chief success in life lies in making herself as much as possible like man—in dress, voice and actions, in sports and achievements of every kind ... The tendency of women to push aside man, supplanting the old spirit of cooperation with him in all the affairs of life, is very disappointing to me".[234] Although he told a reporter in later years that he sometimes felt that by not marrying, he had made too great a sacrifice to his work,[32] Tesla chose to never pursue or engage in any known relationships, instead finding all the stimulation he needed in his work.

Tesla was asocial and prone to seclude himself with his work.[235][236][125][237] However, when he did engage in a social life, many people spoke very positively and admiringly of Tesla. Robert Underwood Johnson described him as attaining a "distinguished sweetness, sincerity, modesty, refinement, generosity, and force".[32] His secretary, Dorothy Skerrit, wrote: "his genial smile and nobility of bearing always denoted the gentlemanly characteristics that were so ingrained in his soul".[33] Tesla's friend, Julian Hawthorne, wrote, "seldom did one meet a scientist or engineer who was also a poet, a philosopher, an appreciator of fine music, a linguist, and a connoisseur of food and drink".[238]

Tesla could be harsh at times and openly expressed disgust for overweight people, such as when he fired a secretary because of her weight.[248] He was quick to criticize clothing; on several occasions, Tesla directed a subordinate to go home and change her dress.[229] When Thomas Edison died, in 1931, Tesla contributed the only negative opinion to The New York Times, buried in an extensive coverage of Edison's life:

He had no hobby, cared for no sort of amusement of any kind and lived in utter disregard of the most elementary rules of hygiene ... His method was inefficient in the extreme, for an immense ground had to be covered to get anything at all unless blind chance intervened and, at first, I was almost a sorry witness of his doings, knowing that just a little theory and calculation would have saved him 90 percent of the labor. But he had a veritable contempt for book learning and mathematical knowledge, trusting himself entirely to his inventor's instinct and practical American sense.[249]

Beliefs

On experimental and theoretical physics

Tesla disagreed with the theory of atoms being composed of smaller subatomic particles, stating there was no such thing as an electron creating an electric charge. He believed that if electrons existed at all, they were some fourth state of matter or "sub-atom" that could exist only in an experimental vacuum and that they had nothing to do with electricity.[250][251] Tesla believed that atoms are immutable—they could not change state or be split in any way. He was a believer in the 19th-century concept of an all-pervasive "ether" that transmitted electrical energy.[252]

Tesla was generally antagonistic towards theories about the conversion of matter into energy.[253] He was also critical of Einstein's theory of relativity, saying:

I hold that space cannot be curved, for the simple reason that it can have no properties. It might as well be said that God has properties. He has not, but only attributes and these are of our own making. Of properties we can only speak when dealing with matter filling the space. To say that in the presence of large bodies space becomes curved is equivalent to stating that something can act upon nothing. I, for one, refuse to subscribe to such a view.[254]

Tesla claimed to have developed his own physical principle regarding matter and energy that he started working on in 1892,[33] and in 1937, at age 81, claimed in a letter to have completed a "dynamic theory of gravity" that "[would] put an end to idle speculations and false conceptions, as that of curved space". He stated that the theory was "worked out in all details" and that he hoped to soon give it to the world.[255] Further elucidation of his theory was never found in his writings.[256]

Tesla expressed the belief that human "pity" had come to interfere with the natural "ruthless workings of nature". Though his argumentation did not depend on a concept of a "master race" or the inherent superiority of one person over another, he advocated for eugenics. In a 1937 interview he stated:

... man's new sense of pity began to interfere with the ruthless workings of nature. The only method compatible with our notions of civilization and the race is to prevent the breeding of the unfit by sterilization and the deliberate guidance of the mating instinct ... The trend of opinion among eugenists is that we must make marriage more difficult. Certainly no one who is not a desirable parent should be permitted to produce progeny. A century from now it will no more occur to a normal person to mate with a person eugenically unfit than to marry a habitual criminal.[260]

In 1926, Tesla commented on the ills of the social subservience of women and the struggle of women toward gender equality, and indicated that humanity's future would be run by "Queen Bees". He believed that women would become the dominant sex in the future.[261]

Tesla made predictions about the relevant issues of a post-World War I environment in a printed article, "Science and Discovery are the great Forces which will lead to the Consummation of the War" (20 December 1914).[262] Tesla believed that the League of Nations was not a remedy for the times and issues.[25]

On religion

Tesla was raised an Orthodox Christian. Later in life he did not consider himself to be a "believer in the orthodox sense," said he opposed religious fanaticism, and said "Buddhism and Christianity are the greatest religions both in number of disciples and in importance".[263] He also said "To me, the universe is simply a great machine which never came into being and never will end" and "what we call 'soul' or 'spirit,' is nothing more than the sum of the functionings of the body. When this functioning ceases, the 'soul' or the 'spirit' ceases likewise".[263]

Many of Tesla's writings are freely available online,[265] including the article "The Problem of Increasing Human Energy," published in The Century Magazine in 1900,[266] and the article "Experiments With Alternate Currents Of High Potential And High Frequency," published in his book Inventions, Researches and Writings of Nikola Tesla.[267][268]

Legacy and honors

Tesla's legacy has endured in books, films, radio, TV, music, live theater, comics, and video games. The impact of the technologies invented or envisioned by Tesla is a recurring theme in several types of science fiction.

Songs

Ships

SS Nikola Tesla, a Liberty Ship laid down 31 August 1943, launched 25 September 1943, sold from government service in 1947, and scrapped 1970

Plaques and memorials

The Nikola Tesla Memorial Centre in Smiljan, Croatia, opened in 2006. It features a statue of Tesla designed by sculptor Mile Blažević.[11][286]

A plaque depicting a relief of Nikola Tesla is present on the Old City Hall (Zagreb) in Zagreb, Croatia's capital, commemorating his proposal to build an alternating currentpower station, which he made to the city council.[287] The plaque quotes Tesla's statement, given in the building on 24 May 1892, which reads: "As a son of this country, I consider it my duty to help the City of Zagreb in every way, either through counsel or through action" (Croatian: "Smatram svojom dužnošću da kao rođeni sin svoje zemlje pomognem gradu Zagrebu u svakom pogledu savjetom i činom").[288]

On 7 July 2006, on the corner of Masarykova and Preradovićeva streets in the Lower Town area in Zagreb, a monument of Tesla was unveiled. This monument was designed by Ivan Meštrović in 1952 and was transferred from the Zagreb-based Ruđer Bošković Institute where it had spent previous decades.[24][289]

A monument of Tesla standing on a portion of an alternator was established at Queen Victoria Park in Niagara Falls, Ontario, Canada. The monument was officially unveiled on 9 July 2006 on the 150th anniversary of Tesla's birth. The monument was sponsored by St. George Serbian Church, Niagara Falls, and designed by Les Drysdale of Hamilton, Ontario.[291][292] Drysdale's design was the winning design from an international competition.[293]

In 2012 Jane Alcorn, president of the nonprofit group Tesla Science Center at Wardenclyffe, and Matthew Inman, creator of web cartoon The Oatmeal, raised a total of $2,220,511 – $1,370,511 from a campaign and $850,000 from a New York State grant—to buy the property where Wardenclyffe Tower once stood and eventually turn it into a museum.[295][296] The group began negotiations to purchase the Long Island property from Agfa Corporation in October 2012.[297] The purchase was completed in May 2013.[298] The preservation effort and history of Wardenclyffe is the subject of a documentary by Tesla activist/filmmaker Joseph Sikorski called Tower to the People—Tesla's Dream at Wardenclyffe Continues.[299]

A commemorative plaque honoring Nikola Tesla was installed on the façade of the New Yorker Hotel by the IEEE.[300]

An intersection named after Tesla, Nikola Tesla Corner, is at the intersection of Sixth Avenue and 40th Street in Manhattan, New York City. The placement of the sign was due to the efforts of the Croatian Club of New York in cooperation with New York City officials, and Dr. Ljubo Vujovic of the Tesla Memorial Society of New York.[301]

A full-size, crowdfunded statue honoring Tesla with free Wi-Fi and a time capsule (to be opened on the 100th anniversary of Tesla's death, 7 January 2043) was unveiled on 7 December 2013 in Palo Alto, California (260 Sheridan Avenue).[303]

^Cheney 2011, p. 25, "The tiny house in which he was born stood next to the Serbian Orthodox Church presided over by his father, the Reverend Milutin Tesla, who sometimes wrote articles under the nom-de-plume 'Man of Justice'".

^Carlson 2013, p. 14, "Following a reprimand at school for not keeping his brass buttons polished, he quit and instead chose to become a priest in the Serbian Orthodox Church".

^Burgan 2009, p. 17, "Nikola's father, Milutin was a Serbian Orthodox priest and had been sent to Smiljan by his church.".

^Tesla's contemporaries remembered that on a previous occasion Machine Works manager Batchelor had been unwilling to give Tesla a $7 a week pay raise (Seifer – Wizard: The Life and Times of Nikola Tesla, p. 38)

^Tesla's own experiments led him to erroneously believe Hertz had misidentified a form of conduction instead of a new form of electromagnetic radiation, an incorrect assumption that Tesla would hold on to for a couple of decades.(Carlson, pp-127-128)(White, Nikola Tesla: The Guy Who DIDN'T "Invent Radio")

^ abNikola Tesla On His Work With Alternating Currents and Their Application to Wireless Telegraphy, Telephony, and Transmission of Power, Leland I. Anderson, 21st Century Books, 2002, p. 109, ISBN1-893817-01-6.

^Malanowski, Gregory (2011). The Race for Wireless: How Radio was Invented (or Discovered?). AuthorHouse. p. 36. ISBN978-1-4634-3750-3. Tesla was definitely asocial, a loner. Although in his younger years he was immensely popular and admired by many rich, socialite women, there were no women in his life.

^McNichol, Tom (2011). AC/DC: The Savage Tale of the First Standards War. John Wiley & Sons. pp. 163–64. ISBN978-1-118-04702-6. Tesla's peculiar nature made him a solitary man, a loner in a field that was becoming so complex that it demanded collaboration.

^Belohlavek, Peter; Wagner, John W (2008). Innovation: The Lessons of Nikola Tesla. Blue Eagle. p. 43. ISBN978-987-651-009-7. This was Tesla: a scientist, philosopher, humanist, and ethical man of the world in the truest sense.

^Seifer, Marc J (1996). Wizard: the life and times of Nikola Tesla: biography of a genius. Citadel Press. p. 506. ISBN978-0-8065-1960-9. Frank Jenkins, "Nikola Tesla: The Man, Engineer, Inventor, Humanist and Innovator," in Nikola Tesla: Life and Work of a Genius (Belgrade: Yugoslav Society for the Promotion of Scientific Knowledge, 1976), pp. 10–21.

The Order of the White Lion is the highest order of the Czech Republic. It continues a Czechoslovak order of the name created in 1922 as an award for foreigners. It was inspired by the Czech Nobility Cross created in 1814 by the Emperor and King Francis I, the order was created as an award for merit by Czechoslovakia for foreign citizens. The Order was established in five classes and two divisions and military, Medals were made of gold and silver. The numbers of recipients was originally limited, with the limits changing during years, the Statutes of the order were amended in 1924,1930, and 1936. The badge of the Order was a red enameled star, the ends adorned with small balls. In middle of the star is a lion, taken from the national coat of arms. The reverse or the Star is red enameled, with the coat of arms of the parts of Czechoslovakia. I Class with collar – reserved for heads of state, introduced in 1924, V Class – Knight – limited to 3000 recipients, cross was similar to IV Class, but in silver.

Gold medal Silver medal Subsequent to World War II, the Order of the White Lion became an award to those who had helped liberate Czechoslovakia from occupation by Nazi Germany. Following the surrender of Germany in May 1945, a number of foreign bestowals were made by presenting the Order of the White Lion to senior officers of the Allied militaries. A similar Order with the name, Military Order of the White Lion was instituted in 1945. Dwight D. Eisenhower and George S. Patton are two Americans who received the Military Order of the White Lion after the close of World War II, the Order was remodeled after the change of the official name of Czechoslovakia and its national arms. A new regulation was issued for the order, and was divided into three classes, the Collar was reserved only for foreign heads of state. The supreme grade of the Order of the White Lion, the first class accompanied by a neck chain may only be awarded to Heads of State. Recipients of the Order of the White Lion Orders and Medals of Czechoslovakia including Order of the White Lion State decorations of the Czech Republic

Mains electricity is the general-purpose alternating-current electric power supply. The two principal properties of the power supply and frequency, differ between regions. A voltage of 230 V and a frequency of 50 Hz is used in Europe, most of Africa, most of Asia, most of South America, in North America, the most common combination is 120 V and a frequency of 60 Hz. Other voltages exist, and some countries may have, for example,230 V but 60 Hz and this is a concern to travelers, since portable appliances designed for one voltage and frequency combination may not operate with or may be destroyed by another. In the UK, mains power is generally referred to as the mains. All these parameters vary among regions, the voltages are generally in the range 100–240 V. The two commonly used frequencies are 50 Hz and 60 Hz, single-phase or three-phase power is most commonly used today, although two-phase systems were used early in the 20th century. Foreign enclaves, such as industrial plants or overseas military bases.

Some city areas may use different from that of the surrounding countryside. Regions in a state of anarchy may have no central electrical authority. Many other combinations of voltage and utility frequency were formerly used, direct current has been almost completely displaced by alternating current in public power systems, but DC was used especially in some city areas to the end of the 20th century. The modern combinations of 230 V/50 Hz and 120 V/60 Hz, listed in IEC60038, electricity is used for lighting, cooling, electric motors and electronic equipment. The U. S. Energy Information Administration has published, Estimated U. S.3 Does not include water heating,4 Includes small electric devices, heating elements, and motors which are not listed above. Does not include electric vehicle charging, electronic appliances, typically use an AC to DC converter to power the device, this is often capable of operation over the approximate range of 100 V to 250 V and at 50 Hz to 60 Hz. The other categories are typically AC applications and usually have more restricted input ranges.

A study by the Building Research Establishment in the UK states that The existing 230 V system is suited to the future of electricity whether through design or Darwinian processes. Any current perceived weakness is generally a result of cost reduction, questions as to whether there are alternatives to the existing 230 V AC system are often overshadowed by legacy issues, the future smart agenda and cost in all but specific situations. Where opportunities do exist they are often for specific parts of the overall load, in many countries, household power is single-phase electric power, with two or three wired contacts at each outlet

A plasma globe or plasma lamp is a clear glass sphere filled with a mixture of various noble gases with a high-voltage electrode in the center of the sphere. Plasma filaments extend from the electrode to the outer glass insulator. Plasma globes were most popular as novelty items in the 1980s, the plasma lamp was invented by Nikola Tesla, during his experimentation with high-frequency currents in an evacuated glass tube for the purpose of studying high voltage phenomena. Tesla called his invention an inert gas discharge tube, the modern plasma lamp design was subsequently developed by Bill Parker, a student at MIT. Although many variations exist, a lamp is usually a clear glass sphere filled with a mixture of various gases at nearly atmospheric pressure. They are driven by high-frequency alternating current at 2–5 kV, the radio-frequency energy from the transformer is transmitted into the gas within the globe through an electrode at its center. A much smaller hollow glass orb can serve as an electrode when it is filled with wool or a conducting fluid that is in communication with the transformer output.

In this case, the energy is admitted into the larger space by capacitive coupling right through the glass. Plasma filaments extend from the electrode to the outer glass insulator. Some globes have a knob that varies the amount of power going to the center electrode. At the very lowest setting that will light or strike the globe and this single tendrils plasma channel engages enough space to transmit this lowest striking energy to the outside world through the glass of the globe. As the power is increased, this single channels capacity is overwhelmed and a second channel forms, a third, the tendrils each compete for a footprint on the inner orb as well. The energies flowing through these are all of the polarity so they repel each other as like charges. Therefore, the capacity of the conducting body to accept radio frequency energy is greater than that of the surrounding air. The energy available to the filaments of plasma within the globe will preferentially flow toward the better acceptor and this flow causes a single filament, from the inner ball to the point of contact, to become brighter and thinner.

The filament is brighter because there is current flowing through it and into the 150 pF capacity, or capacitance, presented by an object, a conducting body. Much of the movement of the filaments is due to heating of the gas around the filament, when gas along the filament is heated, it becomes more buoyant and rises, carrying the filament with it. If the filament is discharging into an object on the side of the globe

An AC motor is an electric motor driven by an alternating current. The rotor magnetic field may be produced by permanent magnets, reluctance saliency, when an AC motor is in steady-state rotation, the magnetic fields of the rotor and stator rotate with little or no slippage. The magnetic forces between the rotor and stator poles create average torque, capable of driving a load at rated speed, asynchronously rotating magnetic fields would produce pulsating or non-average torque. The two main types of AC motors are classified as induction and synchronous, the induction motor always relies on a small difference in speed between the stator rotating magnetic field and the rotor shaft speed called slip to induce rotor current in the rotor AC winding. As a result, the motor cannot produce torque near synchronous speed where induction is irrelevant or ceases to exist. In contrast, the motor does not rely on slip-induction for operation and uses either permanent magnets, salient poles. The synchronous motor produces its rated torque at synchronous speed.

The brushless wound-rotor doubly fed synchronous motor system has an independently excited rotor winding that does not rely on the principles of slip-induction of current. The brushless wound-rotor doubly fed motor is a motor that can function exactly at the supply frequency or sub to super multiple of the supply frequency. Other types of motors include eddy current motors, and AC/DC mechanically commutated machines in which speed is dependent on voltage, alternating current technology was rooted in Michael Faraday’s and Joseph Henry’s 1830-31 discovery that a changing magnetic field can induce an electric current in a circuit. Faraday is usually given credit for this discovery since he published his findings first, in 1832, French instrument maker Hippolyte Pixii generated a crude form of alternating current when he designed and built the first alternator. It consisted of a horseshoe magnet passing over two wound wire coils. Because of ACs advantages in long high voltage transmission, there were many inventors in the United States.

Never practically demonstrated, the design was flawed, as one of the two currents was “furnished by the machine itself. ”In 1886, English engineer Elihu Thomson built an AC motor by expanding upon the induction-repulsion principle and his wattmeter. In 1887, American inventor Charles Schenk Bradley was the first to patent a two-phase AC power transmission with four wires, commutatorless alternating current induction motors seem to have been independently invented by Galileo Ferraris and Nikola Tesla. He invented the first three-phase generator and transformer and combined them into the first complete AC three-phase system in 1891, for this reason, ordinary squirrel-cage motors run at some tens of RPM slower than synchronous speed. Because the rotating field effectively rotates faster than the rotor, it could be said to slip past the surface of the rotor, the difference between synchronous speed and actual speed is called slip, and loading the motor increases the amount of slip as the motor slows down slightly.

Even with no load, internal mechanical losses prevent the slip from being zero, with no load, the speed will be very close to synchronous

The City of New York, often called New York City or simply New York, is the most populous city in the United States. With an estimated 2015 population of 8,550,405 distributed over an area of about 302.6 square miles. Located at the tip of the state of New York. Home to the headquarters of the United Nations, New York is an important center for international diplomacy and has described as the cultural and financial capital of the world. Situated on one of the worlds largest natural harbors, New York City consists of five boroughs, the five boroughs – Brooklyn, Manhattan, The Bronx, and Staten Island – were consolidated into a single city in 1898. In 2013, the MSA produced a gross metropolitan product of nearly US$1.39 trillion, in 2012, the CSA generated a GMP of over US$1.55 trillion. NYCs MSA and CSA GDP are higher than all but 11 and 12 countries, New York City traces its origin to its 1624 founding in Lower Manhattan as a trading post by colonists of the Dutch Republic and was named New Amsterdam in 1626.

The city and its surroundings came under English control in 1664 and were renamed New York after King Charles II of England granted the lands to his brother, New York served as the capital of the United States from 1785 until 1790. It has been the countrys largest city since 1790, the Statue of Liberty greeted millions of immigrants as they came to the Americas by ship in the late 19th and early 20th centuries and is a symbol of the United States and its democracy. In the 21st century, New York has emerged as a node of creativity and entrepreneurship, social tolerance. Several sources have ranked New York the most photographed city in the world, the names of many of the citys bridges, tapered skyscrapers, and parks are known around the world. Manhattans real estate market is among the most expensive in the world, Manhattans Chinatown incorporates the highest concentration of Chinese people in the Western Hemisphere, with multiple signature Chinatowns developing across the city. Providing continuous 24/7 service, the New York City Subway is one of the most extensive metro systems worldwide, with 472 stations in operation.

Over 120 colleges and universities are located in New York City, including Columbia University, New York University, and Rockefeller University, during the Wisconsinan glaciation, the New York City region was situated at the edge of a large ice sheet over 1,000 feet in depth. The ice sheet scraped away large amounts of soil, leaving the bedrock that serves as the foundation for much of New York City today. Later on, movement of the ice sheet would contribute to the separation of what are now Long Island and Staten Island. The first documented visit by a European was in 1524 by Giovanni da Verrazzano, a Florentine explorer in the service of the French crown and he claimed the area for France and named it Nouvelle Angoulême. Heavy ice kept him from further exploration, and he returned to Spain in August and he proceeded to sail up what the Dutch would name the North River, named first by Hudson as the Mauritius after Maurice, Prince of Orange

A few papers of the times listed Teslas lab as about 200 feet East of the Deaf and Blind School and 200 feet North of Pikes Peak Ave. This put it on top of the hill at E. Kiowa St. and N. Foote Ave, Tesla moved there to study the conductive nature of low pressure air, part of his research into wireless transmission of electrical power. The lab possessed the largest Tesla coil ever built,49.25 feet in diameter and this coil reproduced the effects of lightning and its accompanying thunder for the first time in history. Upon his arrival, he told reporters that he planned to conduct wireless telegraphy experiments and he produced artificial lightning, with discharges consisting of millions of volts and up to 135 feet long. Thunder from the energy was heard 15 miles away in Cripple Creek. People walking along the street observed sparks jumping between their feet and the ground, sparks sprang from water line taps when touched. Light bulbs within 100 feet of the lab glowed even when turned off, horses in a livery stable bolted from their stalls after receiving shocks through their metal shoes.

Butterflies were electrified, swirling in circles with blue halos of St. Elmos fire around their wings, while experimenting, Tesla inadvertently faulted a power station generator, causing a power outage. During his time at his laboratory Tesla observed unusual signals from his receiver which he concluded may be communications from another planet, reporters treated it as a sensational story and jumped to the conclusion Tesla was hearing signals from Mars. On 7 January 1900 Tesla made his entry in his journal while in Colorado Springs. In 1900 Tesla was granted patents for a system of transmitting electrical energy, when Guglielmo Marconi made his famous first-ever transatlantic radio transmission in 1901, Tesla quipped that it was done with 17 Tesla patents, though there is little to support this claim. In 1904, Tesla was sued for debts in Colorado Springs. His lab was torn down in 1904, and its contents were sold two years at auction at the house to satisfy his debts

Mechanical engineering is the discipline that applies the principles of engineering and materials science for the design, analysis and maintenance of mechanical systems. It is the branch of engineering that involves the design, production and it is one of the oldest and broadest of the engineering disciplines. The mechanical engineering field requires an understanding of areas including mechanics, thermodynamics, materials science, structural analysis. Mechanical engineering emerged as a field during the Industrial Revolution in Europe in the 18th century, Mechanical engineering science emerged in the 19th century as a result of developments in the field of physics. The field has evolved to incorporate advancements in technology, and mechanical engineers today are pursuing developments in such fields as composites, mechatronics. Mechanical engineers may work in the field of biomedical engineering, specifically with biomechanics, transport phenomena, bionanotechnology. Mechanical engineering finds its application in the archives of various ancient, in ancient Greece, the works of Archimedes deeply influenced mechanics in the Western tradition and Heron of Alexandria created the first steam engine.

In China, Zhang Heng improved a water clock and invented a seismometer, during the 7th to 15th century, the era called the Islamic Golden Age, there were remarkable contributions from Muslim inventors in the field of mechanical technology. Al-Jazari, who was one of them, wrote his famous Book of Knowledge of Ingenious Mechanical Devices in 1206 and he is considered to be the inventor of such mechanical devices which now form the very basic of mechanisms, such as the crankshaft and camshaft. Newton was reluctant to publish his methods and laws for years, gottfried Wilhelm Leibniz is credited with creating Calculus during the same time frame. On the European continent, Johann von Zimmermann founded the first factory for grinding machines in Chemnitz, education in mechanical engineering has historically been based on a strong foundation in mathematics and science. Degrees in mechanical engineering are offered at universities worldwide. In Spain and most of South America, where neither B. Sc. nor B.

Tech, programs have been adopted, the formal name for the degree is Mechanical Engineer, and the course work is based on five or six years of training. In Italy the course work is based on five years of education, and training, in Greece, the coursework is based on a five-year curriculum and the requirement of a Diploma Thesis, which upon completion a Diploma is awarded rather than a B. Sc. In Australia, mechanical engineering degrees are awarded as Bachelor of Engineering or similar nomenclature although there are a number of specialisations. The degree takes four years of study to achieve. To ensure quality in engineering degrees, Engineers Australia accredits engineering degrees awarded by Australian universities in accordance with the global Washington Accord, before the degree can be awarded, the student must complete at least 3 months of on the job work experience in an engineering firm. Similar systems are present in South Africa and are overseen by the Engineering Council of South Africa

In 1804 the Holy Roman Emperor Francis II, who was ruler of the lands of the Habsburg Monarchy, founded the Empire of Austria. In doing so he created a formal overarching structure for the Habsburg Monarchy, to safeguard his dynastys imperial status he adopted the additional hereditary title of Emperor of Austria. Hungarys affairs remained administered by its own institutions as they had been beforehand, thus under the new arrangements no Imperial institutions were involved in its internal government. The fall and dissolution of the Holy Roman Empire was accelerated by French intervention in the Empire in September 1805, on 20 October 1805, an Austrian army led by general Karl Mack von Leiberich was defeated by French armies near the town of Ulm. The French victory resulted in the capture of 20,000 Austrian soldiers, Napoleons army won another victory at Austerlitz on 2 December 1805. Francis was forced into negotiations with the French from 4 to 6 December 1805, the French victories encouraged rulers of certain imperial territories to assert their formal independence from the Empire.

On 10 December 1805, the prince-electorDuke of Bavaria proclaimed himself King, finally, on 12 December, the Margrave of Baden was given the title of Grand Duke. In addition, each of these new countries signed a treaty with France, the Treaty of Pressburg between France and Austria, signed in Pressburg on 26 December, enlarged the territory of Napoleons German allies at the expense of defeated Austria. Certain Austrian holdings in Germany were passed to French allies—the King of Bavaria, the King of Württemberg, Austrian claims on those German states were renounced without exception. On 12 July 1806, the Confederation of the Rhine was established, comprising 16 sovereigns and this confederation, under French influence, put an end to the Holy Roman Empire. On 6 August 1806, even Francis recognized the new state of things and proclaimed the dissolution of the Holy Roman Empire, as he did not want Napoleon to succeed him

Smiljan is a village in the mountainous region of Western Lika in Croatia. It is located 6 km northwest of Gospić, and fifteen kilometers from the Zagreb-Split highway, Smiljan is famous as the birthplace of scientist Nikola Tesla. It consists of eighteen scattered hamlets, Smiljan resort is located in the central part of the Velebit-Lika plain, on the western edge of the field at the foot of the hill Licko Krcmar. It consists of villages which makes the spatial and functional unit. In the surroundings are Hill-forts Bogdanić, Smiljan and Krčmar, prehistoric tombs and it got its name from the fort Smiljan which ruins are located at hill Vekavac. The oldest traces of settlement on the ground of Smiljan are dating from the Middle, on the hillfort Miljac once was situated necropolis, and were found numerous remains of Iapodian culture. The area of Smiljan was controlled by the Ottoman Empire between 1527–1686, after which the Ottoman rule was expelled from those parts by counts Jerko Rukavina, until that time the Ottoman aghas and Zenković, from Novi near Gospić had estates in Smiljan, Bužim and Trnovac.

After the defeat of the Ottomans in Lika, most of the Bunjevci migrated to Lika, a 1700 church register listed 17 Serbian Orthodox families in the village, who had settled during the Great Turkish War. In 1708 the Roman Catholic parish of Our Lady of Mount Carmel was founded, there is a small chapel, Immaculate Conception of the Virgin Mary. The Serbian Orthodox church of St. Peter and Paul was built in 1765, the re-construction of the Catholic parish church of Our Lady of Mount Carmel was started in 1860, and finished 1864. In 1830 a minor school was founded, during World War II, warfare broke out among ethnic groups. The Ustaše of the Independent State of Croatia killed several hundred Serbs by the Orthodox church in Smiljan, the Ustaše killed most of the Serbs in this and other villages in Gospić district between 1 and 10 August 1941. The Orthodox parish church was destroyed by the Ustaše the same year, the village of Smiljan was incorporated to the Croatian Military Frontier only in 1713, and subsequently registered in the 1712/14 census done in Lika and Krbava.

Most of them were Bunjevci and Carniolians, there were 103 Roman Catholic, and 17 Serbian Orthodox families. In 1746 there lived 2.149 people, with 2.144 people land owners, in 1830 existed 206 houses, with 1880 people, of whom 1.401 Roman Catholic, and 479 Orthodox faith. Note, In 1869 and 1880 contains data for villages Rastoka and Smiljansko Polje, a nearby village of Smiljansko Polje has 135 residents. Today, Teslas birth house, together with the Serbian Orthodox church of St. Peter and Paul, there are various exhibits of Teslas inventions and a museum where the details of the inventors life are shown. There is a hall in a nearby building

A vacuum variable capacitor is a variable capacitor which uses a high vacuum as the dielectric instead of air or other insulating material. This allows for a voltage rating using a smaller total volume. There are several different designs in vacuum variables, the most common form is inter-meshed concentric cylinders, which are contained within a glass or ceramic vacuum envelope, similar to an electron tube. A metal bellows is used to maintain a vacuum seal while allowing positional control for the parts of the capacitor. Nikola Tesla filed a patent in 1896 for a vacuum capacitor, the original use was to enhance the quality of the electrical components for handling currents of high frequency and potential. These components were necessary for the DC impulse research which Tesla was studying, commercial products have been available since 1942. Vacuum variable capacitors are used in high-voltage applications,5000 volts. They are used in equipment such as high-powered broadcast transmitters, amateur radio RF amplifiers, industrially they are used in plasma generating equipment, for dielectric heating, and in semiconductor manufacturing.

Other variations of vacuum capacitors include capacitors, which are designed very much like the variable versions with the exception of an adjustment mechanism. When compared to other variable capacitors, vacuum variables tend to be more precise and this is due to the vacuum itself. Because of the chamber, the dielectric constant remains the same over a wider range of operating conditions. With air variable capacitors, the air moving around the plates may change the value slightly, often it is not much, Vacuum variable capacitors are generally more expensive than air variable capacitors. This is primarily due to their design and the materials used, although most use copper and glass, some may use other materials such as ceramics and metals such as gold and silver. Vacuum variables vary in adjustment mechanisms, comet Vacuum variable capacitor Jennings Vacuum variable capacitor GLVAC Vacuum variable capacitor Introduction to capacitors

A vertical take-off and landing aircraft is one that can hover, take off, and land vertically. This classification includes fixed-wing aircraft as well as helicopters and other aircraft with powered rotors, some VTOL aircraft can operate in other modes as well, such as CTOL, STOL, and/or STOVL. Others, such as helicopters, can only operate by VTOL. VTOL is a subset of V/STOL, generally speaking, VTOL aircraft capable of STOVL use it wherever possible, since it typically significantly increases takeoff weight, range or payload compared to pure VTOL. The helicopters form of VTOL allows it to take off and land vertically, to hover, and to fly forwards and these attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft would usually not be able to take off or land. On the other hand, the rotor blades restrict the maximum speed to about 250 miles per hour of at least conventional helicopters. Autogyros are known as gyroplanes or gyrocopters, the rotor is unpowered and rotates freely in the airflow as the craft travels forward, so the craft needs a conventional powerplant to provide thrust.

An autogyro is not intrinsically capable of VTOL, for VTO the rotor must be spun up to speed by an auxiliary drive, gyrodynes are known as compound helicopters or compound gyroplanes. A gyrodyne has the rotor of a helicopter with a separate forward thrust system of an autogyro. Apart from take-off and landing the rotor may be unpowered and autorotate, designs may include stub wings for added lift. A cyclogyro or cyclocopter has a wing whose axis and surfaces remain sideways across the airflow. A convertiplane takes off under rotor lift like a helicopter, transitions to fixed-wing lift in forward flight, a tiltrotor or proprotor tilts its propellers or rotors vertically for VTOL and tilts them forwards for horizontal wing-borne flight, while the main wing remains fixed in place. Similar to tiltrotor concept, but with turbojet or turbofan engines intead of ones with propellers, a tiltwing has its propellers or rotors fixed to a conventional wing and tilts the whole assembly to transition between vertical and horizontal flight.

A tail-sitter sits vertically on its tail for takeoff and landing, Thrust vectoring is a technique used for jet and rocket engines, where the direction of the engine exhaust is varied. In VTOL, the exhaust can be varied between vertical and horizontal thrust, a lift jet is an auxiliary jet engine used to provide lift for VTOL operation, but may be shut down for normal wing-borne flight. Lift fan is a configuration in which lifting fans are located in large holes in an otherwise conventional fixed wing or fuselage. It is used for V/STOL operation, the aircraft takes off using the fans to provide lift, transitions to fixed-wing lift in forward flight. Several experimental craft have flown, but only the F-35 Lightning II entered into production

Sofia is the capital and largest city of Bulgaria. The city has a population of 1.26 million, while 1.68 million people live in its metropolitan area, the city is located at the foot of Vitosha Mountain in the western part of the country, within less than 50 kilometres drive from the Serbian border. Its location in the centre of the Balkan peninsula means that it is the midway between the Black Sea and the Adriatic Sea, whereas the Aegean Sea is the closest to it, Sofia has been an area of human habitation since at least 7000 BC. Being Bulgarias primate city, Sofia is a hometown of many of the local universities, cultural institutions. Sofia is one of the top 10 best places for business in the world. Sofia is Europes most affordable capital to visit as of 2013, for the longest time the city possessed a Thracian name, derived from the tribe Serdi, who were either of Thracian, Celtic, or mixed Thracian-Celtic origin. It seems that the first written mention of Serdica was made during his reign, during the Romanscivitas Serdenisium was mentioned the brightest city of the Serdi in official inscriptions.

The city was major throughout the past ever since Antiquity, when Roman emperor Constantine the Great referred to it as my Rome, other names given to Sofia, such as Serdonpolis and Triaditza, were mentioned by Byzantine Greek sources or coins. The Slavic name Sredets, which is related to middle and to the citys earliest name, the city was called Atralissa by the Arab traveller Idrisi and Strelisa, Stralitsa or Stralitsion by the Crusaders. The name Sofia comes from the Saint Sofia Church, as opposed to the prevailing Slavic etymology among Bulgarian cities and towns. It is ultimately derived from the Egyptian Kemetic word sbÅ, meaning star, door and wisdom and this was a tradition of collection of wise literature, shared between Mediterranean cultures, which was called sophia in Greek. In these documents the city is called Sofia, but at the time the region and the citys inhabitants are still called Sredecheski. The city became popular to the Ottomans by the name Sofya. In 1879 there was a dispute about what the name of the new Bulgarian capital should be, the citys name is pronounced by Bulgarians with a stress on the o, in contrast with the tendency of foreigners to place the stress on i.

The female given name Sofia is pronounced by Bulgarians with a stress on the i, Sofia has an area of 492 km2, while Sofia City Province has an area of 1344 km2. Sofias development as a significant settlement owes much to its position in the Balkans. It is situated in western Bulgaria, at the foot of the Vitosha mountain, in the Sofia Valley that is surrounded by the Balkan mountains to the north. The valley has an altitude of 550 metres

The Austrian Empire was a Central European multinational great power from 1804 to 1867, created by proclamation out of the realms of the Habsburgs. During its existence, it was the third most populous empire after the …

The City of New York, usually called either New York City or simply New York, is the most populous city in the United States and in the U.S. state of New York. With an estimated 2017 population of 8,622,698 distributed over a land area of about 302.6 square miles, New York is …

The Nikola Tesla Museum is a museum dedicated to honoring and displaying the life and work of Nikola Tesla. The museum is located in the central area of Belgrade, Serbia. It holds more than 160,000 original documents, over 2,000 books and journals …

Graz University of Technology is one of five universities in Styria, Austria. It was founded in 1811 by Archduke John of Austria and currently comprises seven faculties. The university is a public university. It offers 18 bachelors and 33 masters …

Alternating current is an electric current which periodically reverses direction, in contrast to direct current which flows only in one direction. Alternating current is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy …

High voltage transmission lines deliver power from electric generation plants over long distances using alternating current. These lines are located in eastern Utah.

The prototype of the ZBD transformer on display at the Széchenyi István Memorial Exhibition, Nagycenk in Hungary

A schematic representation of long distance electric power transmission. C=consumers, D=step down transformer, G=generator, I=current in the wires, Pe=power reaching the end of the transmission line, Pt=power entering the transmission line, Pw=power lost in the transmission line, R=total resistance in the wires, V=voltage at the beginning of the transmission line, U=step up transformer.

An induction motor or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. An induction motor can therefore be made without electrical connections to …

Three-phase totally-enclosed fan-cooled (TEFC) induction motor with end cover on the left, and without end cover to show cooling fan. In TEFC motors, interior heat losses are dissipated indirectly through enclosure fins, mostly by forced air convection.

Cutaway view through stator of TEFC induction motor, showing rotor with internal air circulation vanes. Many such motors have a symmetric armature, and the frame may be reversed to place the electrical connection box (not shown) on the opposite side.

A model of Nikola Tesla's first induction motor at the Tesla Museum in Belgrade, Serbia

Squirrel cage rotor construction, showing only the center three laminations

A Tesla coil is an electrical resonant transformer circuit designed by inventor Nikola Tesla in 1891. It is used to produce high-voltage, low-current, high frequency alternating-current electricity. Tesla experimented with a number of different configurations consisting of two, or sometimes three …

Unipolar coil design widely used in modern coils. The primary is the flat red spiral winding at bottom, the secondary is the vertical cylindrical coil wound with fine red wire. The high voltage terminal is the aluminum torus at the top of the secondary coil.

Bipolar coil, used in the early 20th century. There are two high voltage output terminals, each connected to one end of the secondary, with a spark gap between them. The primary is 12 turns of heavy wire, which is located at the midpoint of the secondary to discourage arcs between the coils.

A modern torpedo is a self-propelled weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with its target or in proximity to it. — Historically, it was called an automotive, automobile …

A vertical take-off and landing aircraft is one that can hover, take off, and land vertically. This classification can include a variety of types of aircraft including fixed-wing aircraft as well as helicopters and other aircraft with powered rotors, such as cyclogyros/cyclocopters and …

Wardenclyffe Tower, also known as the Tesla Tower, was an early experimental wireless transmission station designed and built by Nikola Tesla in Shoreham, New York in 1901–1902. Tesla intended to transmit messages, telephony and even facsimile images across the Atlantic to England and …

1904 image of Wardenclyffe Tower

Tesla with his "magnifying transmitter", Colorado Springs, 1899, in photo taken for his 1900 Century Magazine article. This photo was a double exposure; Tesla was not actually in the room when the device was operating.

Stanford White Building at the corner of Tesla Street and NY&nbsp;25A (2009)

Wireless power transfer, wireless power transmission, wireless energy transmission, or electromagnetic power transfer is the transmission of electrical energy without wires as a physical link. In a wireless power transmission system, a transmitter device, driven by electric power from …

Inductive charging pad for LG smartphone, using the Qi system, an example of near-field wireless transfer. When the phone is set on the pad, a coil in the pad creates a magnetic field which induces a current in another coil, in the phone, charging its battery.

A laser beam centered on a panel of photovoltaic cells provides enough power to a lightweight model airplane for it to fly.

Sofia is the capital and largest city of Bulgaria. The city is at the foot of Vitosha Mountain in the western part of the country. Being in the centre of the Balkan peninsula, it is midway between the Black Sea and …

Serbian Americans, in Serbian, the community is also known as American Serbs, are United States citizens of Serb ethnic ancestry. As of 2012, there are 199,080 American citizens of "Serbian ancestry" who …

Electrical engineering is a professional engineering discipline that generally deals with the study and application of electricity, electronics, and electromagnetism. This field first became an identifiable occupation in the later half of the 19th century after commercialization of the electric …

Some electrical engineers design complex power systems on a macroscopic level.

Electrical engineers also design microscopic electronic devices and electronic circuitry, which achieved the record setting length of 1 nanometer for a single logic gate.

The discoveries of Michael Faraday formed the foundation of electric motor technology

Mechanical engineering is the discipline that applies engineering, physics, engineering mathematics, and materials science principles to design, analyze, manufacture, and maintain mechanical systems. It is one of the oldest and broadest of the engineering disciplines. — The mechanical engineering …

The electric power industry covers the generation, transmission, distribution and sale of electric power to the general public and industry. The commercial distribution of electric power started in 1882 when electricity was produced for electric lighting. In the 1880s and 1890s, growing economic …

The Westinghouse Electric Corporation was an American manufacturing company. It was founded on January 8, 1886, as Westinghouse Electric Company and later renamed Westinghouse Electric Corporation by its founder George Westinghouse. George Westinghouse had previously founded the …

George Westinghouse

1888 Westinghouse brochure advertising their Alternating system

Share of the Westinghouse Electric and Manufacturing Company, issued March 31, 1910

Colorado Springs is a home rule municipality that is the largest city by area in Colorado as well as the county seat and the most populous municipality of El Paso County, Colorado, United States. Colorado Springs is located in the east central portion of the state. It is situated on Fountain Creek …

Radio control is the use of radio signals to remotely control a device. Radio control is used for control of model vehicles from a hand-held radio transmitter. Industrial, military, and scientific research organizations make use of radio-controlled vehicles …

A vacuum variable capacitor is a variable capacitor which uses a high vacuum as the dielectric instead of air or other insulating material. This allows for a higher voltage rating than an air dielectric using a smaller total volume. However, many dielectrics have higher breakdown field strengths …

The Serbian Cyrillic alphabet is an adaptation of the Cyrillic script for Serbo-Croatian, developed in 1818 by Serbian linguist Vuk Karadžić. It is one of the two alphabets used to write standard modern Serbian, Bosnian …

The Edison Machine Works was a manufacturing company set up to produce dynamos, large electric motors, and other components of the electrical illumination system being built by Thomas A. Edison in New York City. — History — The need for equipment in the development of a large scale electric …

1896 view Schenectady, NY location after it had become General Electric

The World Wireless System was a turn of the 20th century proposed telecommunications and electrical power delivery system designed by inventor Nikola Tesla based on his theories of using Earth and its atmosphere as electrical conductors. He claimed this system would allow for "the transmission of …

Tesla sits in front of a spiral coil from a high-voltage transformer at his East Houston St., New York laboratory in 1896

1925 artist's conception of what Tesla's wireless power transmission system might look like in the future, powering aircraft and lighting the city in the background.

An AC motor is an electric motor driven by an alternating current. The AC motor commonly consists of two basic parts, an outside stator having coils supplied with alternating current to produce a rotating magnetic field, and an inside rotor attached to the output shaft producing a second …

An industrial type of AC motor with electrical terminal box at the top and output rotating shaft on the left. Such motors are widely used for pumps, blowers, conveyors and other industrial machinery.

A plasma globe or plasma lamp is a clear glass container filled with a mixture of various noble gases with a high-voltage electrode in the center of the container. — When voltage is applied, a plasma is formed within the …

A plasma globe with filaments extending between the inner and outer spheres

A violet ray is an antique medical appliance used during the early 20th century to discharge in electrotherapy. Their construction usually featured a disruptive discharge coil with an interrupter to apply a high voltage, high frequency, low current to the human body for therapeutic purposes. — Overview …

Antique violet ray set with glass electrode (left) and control box. When energized, the glass emitted a violet glow (inset, center)

The Tesla Experimental Station was a Colorado Springs laboratory built in 1899 by inventor Nikola Tesla and used that year for his study of the use of high-voltage, high-frequency electricity in wireless power transmission. — Location — The Experimental Station was located on empty land on the …

Smiljan is a village in the mountainous region of Western Lika in Croatia. It is located 6 km northwest of Gospić, and fifteen kilometers from the Zagreb-Split highway; its population is 418. Smiljan is famous as the birthplace of inventor, engineer and …

Resonant inductive coupling or magnetic phase synchronous coupling is a phenomenon with inductive coupling where the coupling becomes stronger when the "secondary" side of the loosely coupled coil resonates. A resonant transformer of this type is often used in analog circuitry as a …

Example receiver coil. The coil is loaded with a capacitor and two LEDs. The coil and the capacitor form a series LC circuit which is tuned to a resonant frequency that matches the transmission coil located inside of the brown matt. Power is transmitted over a distance of thirteen inches.

Teleoperation indicates operation of a system or machine at a distance. It is similar in meaning to the phrase "remote control" but is usually encountered in research, academic and technical environments. It is most commonly associated with robotics and mobile robots but …

An IED detonator, a telemanipulator for investigating potentially explosive devices